Description of the Prior Art
The raw sewage discharged from human bodies is typically discharged into a sewage system by use of a flush toilet or the like and then is flowed into a river after being temporarily contained in a holding tank and purified therein. However, at events such as festivals, athletic events, fairs, meetings and the like, temporary toilet facilities must be provided to dispose of raw human waste.
Employed conventionally are movable temporary toilets, most of which have a tank for temporarily storing the raw sewage therein. However, the temporary toilets have the problem that the raw sewage contained in the tank must be sucked into the vacuum truck for collection, which is laborious and time consuming and is unhygienic.
Transportation vehicles, such as buses, trains, vessels, etc., which operate over long distance are provided with a tank exclusively used for storing and holding the discharged raw sewage. The raw sewage in this tank is subjected to a deodorizing treatment by chemicals and thereafter is collected by the vacuum truck.
As mentioned above, the raw sewage in conventional temporary toilets or movable transportation facilities is contained as it is discharged from the human body and is collected thereafter. Accordingly, the storing method, the collection method and the disposal method are not modern and are very unhygienic.
In an attempt to ameliorate the above problems, there have been proposed several hygienic disposal methods. In one method, for example, chemicals are introduced into the tank where the raw sewage is contained to thereby prevent the bad smell and to effect sterilization of the sewage. This method, however, cannot be used for a long period of time because the chemicals become diluted and costs are high.
In another method, the raw sewage is contained in a bag made of vinyl and the like to prevent the diffusion of the bad smell. This method, however, requires a vinyl bag of large size and involves a high cost for disposal thereof, and it is troublesome to separate the raw sewage from the bag.
In still another method, the discharged raw sewage is directly dried by use of heat from a burner, etc. Since the primary component of raw sewage is liquid, a large amount of heat energy is required to remove the liquid and it takes a long time to effect disposal of the raw sewage.
In view of the drawbacks of the conventional methods of disposing of the raw sewage, the present inventor proposed a disposing apparatus having a casing provided with stirring blades and heat holding bodies therein in which the raw sewage is stirred by the rotation of the stirring blades and heated by heat generated by the heat holding bodies whereby the raw sewage is dried in a short period of time as disclosed in Japanese Patent Laid-Open Publication Nos. 63-124150, 63-172852, 63-190857, 63-292789 and Application No. 63-198858, corresponding U.S. Ser. No. 315 028, now U.S. Pat. No. 4 999 930, and its divisional application Ser. No. 609 378, filed Nov. 5, 1990. According to the proposed disposal methods, the raw sewage is heated, vaporized in a casing and the liquid component of the raw sewage is vaporized and diffused into the ambient atmosphere. Before the liquid component is diffused, the components which cause a bad smell are resolved by a catalyst so that the vapor is diffused into the atmosphere as an odorless vapor. It was preferably to employ such a method in view of environmental hygiene and preservation even if such method is employed in crowded buildings and/or by throngs of people.
Other related U.S. applications are Ser. No. 575 910, filed Aug. 29, 1990, Ser. No. 784 541 filed Nov. 18, 1991, Ser. No. 784 595 filed Nov. 18, 1991 and Ser. No. 809 962 filed Dec. 18, 1991
It is very hygienic to evaporate and dry the raw sewage contained in the airtight tank and such operations can be carried out systematically, which results in not causing a burden to the operators. However, according to the raw sewage disposal apparatus proposed by the inventor, an airtight vessel (drying cauldron) which accommodates the raw sewage therein is heated at the lower portion thereof by a heater, etc. so that the liquid component of the raw sewage is evaporated. Since the liquid component of the raw sewage is evaporated and the raw sewage is dried, bad smell is not dispersed outside the apparatus, which contributes to the hygienic disposal of the raw sewage. The bad smell component among the evaporated liquid component is oxidized by being forced to contact a catalyst so that the evaporated liquid component can be discharged to the atmosphere with an odorless state. As evident from this, the present invention is to provide a hygienic disposal structure different from the conventional privy type temporary toilet.
However, there remains several percent of fibrous substances, ash, etc. among the discharged raw sewage which cannot be evaporated. If the liquid component of the raw sewage is evaporated and the raw sewage is dried in the airtight vessel, the fibrous substance and ash, etc. remain and accumulate in the vessel. It was necessary to remove and clean the residual substances and dust in the vessel for continuous use of the raw sewage disposal apparatus for a long time. Accordingly, the conventional raw sewage disposal apparatus is equipped with a cleaning operation mechanism for collecting the dust. The cleaning operation mechanism evaporates the liquid component of the raw sewage and dries the raw sewage in the vessel and subjects them to the cleaning operation so as to always keep the inside of the vessel clean. If the raw sewage is not subjected to the cleaning operation, the dust and dregs accumulate in the vessel, which impedes the drying operation of the raw sewage.
In the cleaning operation of the vessel for evaporating the liquid component of the raw sewage and drying the raw sewage, a compressed air is jetted from a part of the vessel so that the dust formed by the residual substances which is formed by the evaporation of the liquid component is blown up and discharged together with air outside the vessel. The discharged dust is separated from air using a cyclone dust collector. In the cyclone dust collector, the discharged air is circled in a vortex at high speed whereby the heavy dust which is circled with air drops and is separated from the air. The dust separated from the air by the cyclone dust collector is collected by a dust collection box while air alone is forced to contact the catalyst and is diffused outside the raw sewage disposal apparatus. Although the cyclone dust collector has a simple structure, it should be precisely manufactured since air should be circled in a vortex. Even if the dust can be separated from air by permitting air to circle at high speed, the fine dust is not always separated from the air and is liable to diffuse outside the raw sewage disposal apparatus. Under the circumstances, there is a desire to develop a mechanism for separating the dust from the air.
To achieve the above object, the raw sewage disposal apparatus according the present invention, in a preferred embodiment, comprises a heat-resistant vessel for containing raw sewage therein, a heating means provided under the vessel for heating the vessel to thereby evaporate the liquid component of the raw sewage and dry the raw sewage in the vessel, a stirring means having a plurality of stirring blades for stirring the raw sewage in the vessel, a plurality of spherical heat-holding bodies contained in the vessel, an introduction pipe communicating with the side surface of the vessel, a stool connected to the upper end of the introduction pipe, a gear box mounted on the vessel and having a rotary shaft which stirs the raw sewage, a heating pipe which has a heater therein and communicates with a first air supply means at one open end thereof and with a catalyst box at the other open end thereof, a second air supply means communicating with the vessel which supplies fresh air into the vessel, the catalyst box containing catalyst and filter therein and communicating with the second air supply means by way of an exhaust pipe and an ejector, an air introduction pipe communicating with the side surface of the heating pipe at one open end thereof, the air introduction pipe being branched into two pipes at the upper open end thereof, a discharge pipe communicating with the vessel at one open end thereof for exhausting vapor formed by the evaporation of the liquid component of the raw sewage in the vessel, the discharge pipe communicating with the one branched pipe of the air introduction pipe at the side surface thereof by way of a first closing valve, a cleaning pipe communicating with the other end of the discharge pipe by way of a second closing valve, a dust collector connected to the cleaning pipe, a return pipe communicating with the dust collector at one open end thereof and communicating with the other branched pipe of the air introduction pipe by way of a third closing valve.
According to the present invention, the raw sewage discharged in the stool passes the shutter mechanism and drops into the introduction pipe and is contained in the vessel (i.e., the drying cauldron). Since the drying cauldron is heated by the heater, etc. from the outside thereof, the liquid component, which is a main component of the raw sewage contained therein, is evaporated as vapor. The vapor flows toward the catalyst box by way of the discharge pipe. Hot air is always supplied to the catalyst box from a heating pipe so that the catalyst in the catalyst box is always heated. At this state, if the vapor formed by the evaporation of the liquid component flows into the catalyst box and contacts the catalyst, a bad smell component contained in the vapor is subjected to oxidation and reduction and is thereby made odorless. Accordingly, the bad smell cannot be diffused outside the raw sewage disposal apparatus.
After the drying operation is performed for a given time, the closing valve in the discharge pipe is closed and at the same time the closing valve in the dust collector is opened so that the drying cauldron communicates with the dust collection box. Thereafter, compressed air is jetted to the drying cauldron to thereby blow up the dust after the liquid component is evaporated and successively the dust is permitted to flow into the dust collection box together with the air from the discharge pipe. Since the collection bag made of cloth or paper is housed in the dust collection box, the residual substances are caught by this collection bag so that pure air alone is diffused outside the raw sewage disposal apparatus. The collection bag can catch even fine dust. If a given amount of dust is contained in the collection bag, the collection bag containing dust therein can be disposed of. With such an arrangement, the structure of the raw sewage disposal apparatus is simplified because of non-employment of the cyclone dust collector to thereby catch even the fine dust so that environmental pollution can be prevented.